2. PARTICLES (From Atoms to Quarks and Leptons) Structure of Matter
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Jul/Aug 2013
I NTERNATIONAL J OURNAL OF H IGH -E NERGY P HYSICS CERNCOURIER WELCOME V OLUME 5 3 N UMBER 6 J ULY /A UGUST 2 0 1 3 CERN Courier – digital edition Welcome to the digital edition of the July/August 2013 issue of CERN Courier. This “double issue” provides plenty to read during what is for many people the holiday season. The feature articles illustrate well the breadth of modern IceCube brings particle physics – from the Standard Model, which is still being tested in the analysis of data from Fermilab’s Tevatron, to the tantalizing hints of news from the deep extraterrestrial neutrinos from the IceCube Observatory at the South Pole. A connection of a different kind between space and particle physics emerges in the interview with the astronaut who started his postgraduate life at CERN, while connections between particle physics and everyday life come into focus in the application of particle detectors to the diagnosis of breast cancer. And if this is not enough, take a look at Summer Bookshelf, with its selection of suggestions for more relaxed reading. To sign up to the new issue alert, please visit: http://cerncourier.com/cws/sign-up. To subscribe to the magazine, the e-mail new-issue alert, please visit: http://cerncourier.com/cws/how-to-subscribe. ISOLDE OUTREACH TEVATRON From new magic LHC tourist trail to the rarest of gets off to a LEGACY EDITOR: CHRISTINE SUTTON, CERN elements great start Results continue DIGITAL EDITION CREATED BY JESSE KARJALAINEN/IOP PUBLISHING, UK p6 p43 to excite p17 CERNCOURIER www. -
The Standard Model
The Standard Model by Christine Sutton In May 1983, the central detector of the UA1 experiment at CERN's proton-antiproton collider showed the tell-tale signature of the long-awaited Z particle as it decays into an electron-positron pair (arrowed). As the electrically neutral carrier of the weak force, the Z° plays a vital role in the Standard Model. The initial evidence from Fermilab (see previous article) for the long awaited sixth ('top') quark puts another rivet in the already firm structure of today's Standard Model of physics. Analysis of the Fermilab CDF data gives a top mass of 174 GeV with an error of ten per cent either way. This falls within the mass band predicted by the sum total of world Standard Model data and underlines our understanding of physics in terms of six quarks and six leptons. Model encompasses all the elemen their interactions emerge. Instead it is In this specially commissioned tary particles we now know and three an amalgam of the best theories we overview, physics writer Christine of the fundamental forces. The basic have, which we can bolt together Sutton explains the Standard building blocks are two sets or because they have enough in com Model. "families" or "matter particles" - the mon to suggest an underlying unity, quarks and the leptons (see page 5). although due to our ignorance the These particles interact with each joins still clearly show. t is nearly 100 years since the other through the exchange of force The structure as a whole rests on a I discovery of the first subatomic carriers or "messengers". -
CONTENTS Group Membership, January 2002 2
CONTENTS Group Membership, January 2002 2 APPENDIX 1: Report on Activities 2000-2002 & Proposed Programme 2002-2006 4 1OPAL 4 2H1 7 3 ATLAS 11 4 BABAR 19 5DØ 24 6 e-Science 29 7 Geant4 32 8 Blue Sky and applied R&D 33 9 Computing 36 10 Activities in Support of Public Understanding of Science 38 11 Collaborations and contacts with Industry 41 12 Other Research Related Activities by Group Members 41 13 Staff Management and Implementation of Concordat 41 APPENDIX 2: Request for Funds 1. Support staff 43 2. Travel 55 3. Consumables 56 4. Equipment 58 APPENDIX 3: Publications 61 1 Group Membership, May 2002 Academic Staff Dr John Allison Senior Lecturer Professor Roger Barlow Professor Dr Ian Duerdoth Senior Lecturer Dr Mike Ibbotson Reader Dr George Lafferty Reader Dr Fred Loebinger Senior Lecturer Professor Robin Marshall Professor, Group Leader Dr Terry Wyatt Reader Dr A N Other (from Sept 2002) Lecturer Fellows Dr Brian Cox PPARC Advanced Fellow Dr Graham Wilson (leave of absence for 2 yrs) PPARC Advanced Fellow James Weatherall PPARC Fellow PPARC funded Research Associates∗ Dr Nick Malden Dr Joleen Pater Dr Michiel Sanders Dr Ben Waugh Dr Jenny Williams PPARC funded Responsive Research Associate Dr Liang Han PPARC funded e-Science Research Associates Steve Dallison core e-Science Sergey Dolgobrodov core e-Science Gareth Fairey EU/PPARC DataGrid Alessandra Forti GridPP Andrew McNab EU/PPARC DataGrid PPARC funded Support Staff∗ Phil Dunn (replacement) Technician Andrew Elvin Technician Dr Joe Foster Physicist Programmer Julian Freestone -
The Discovery of the Higgs Boson at the LHC
Chapter 6 The Discovery of the Higgs Boson at the LHC Peter Jenni and Tejinder S. Virdee 6.1 Introduction and the Standard Model The standard model of particle physics (SM) is a theory that is based upon principles of great beauty and simplicity. The theory comprises the building blocks of visible matter, the fundamental fermions: quarks and leptons, and the fundamental bosons that mediate three of the four fundamental interactions; photons for electromag- netism, the W and Z bosons for the weak interaction and gluons for the strong interaction (Fig. 6.1). The SM provides a very successful description of the visible universe and has been verified in many experiments to a very high precision. It has an enormous range of applicability and validity. So far no significant deviations have been observed experimentally. The possibility of installing a proton-proton accelerator in the LEP tunnel, after the e+e− programme, was being discussed in the 1980’s. At the time there were many profound open questions in particle physics, and several are still present. In simple terms these are: what is the origin of mass i.e. how do fundamental particles acquire mass, and why do they have the masses that they have? Why is there more matter than anti-matter? What is dark matter? What is the path towards unification of all forces? Do we live in a world with more space-time dimensions than the familiar four? The LHC [1, 2] was conceived to address or shed light on these questions. P. Jenni CERN, Geneva, Switzerland Albert-Ludwigs University Freiburg, Freiburg im Breisgau, Germany T. -
ANTIMATTER a Review of Its Role in the Universe and Its Applications
A review of its role in the ANTIMATTER universe and its applications THE DISCOVERY OF NATURE’S SYMMETRIES ntimatter plays an intrinsic role in our Aunderstanding of the subatomic world THE UNIVERSE THROUGH THE LOOKING-GLASS C.D. Anderson, Anderson, Emilio VisualSegrè Archives C.D. The beginning of the 20th century or vice versa, it absorbed or emitted saw a cascade of brilliant insights into quanta of electromagnetic radiation the nature of matter and energy. The of definite energy, giving rise to a first was Max Planck’s realisation that characteristic spectrum of bright or energy (in the form of electromagnetic dark lines at specific wavelengths. radiation i.e. light) had discrete values The Austrian physicist, Erwin – it was quantised. The second was Schrödinger laid down a more precise that energy and mass were equivalent, mathematical formulation of this as described by Einstein’s special behaviour based on wave theory and theory of relativity and his iconic probability – quantum mechanics. The first image of a positron track found in cosmic rays equation, E = mc2, where c is the The Schrödinger wave equation could speed of light in a vacuum; the theory predict the spectrum of the simplest or positron; when an electron also predicted that objects behave atom, hydrogen, which consists of met a positron, they would annihilate somewhat differently when moving a single electron orbiting a positive according to Einstein’s equation, proton. However, the spectrum generating two gamma rays in the featured additional lines that were not process. The concept of antimatter explained. In 1928, the British physicist was born. -
Neutrino Physics Was Certainly Major.'Xxii
Neutrino FRANK CLOSE OXFORD UNIVERSITY PRESS OXFORD UNIVERSITY PRESS Great Clarendon Street, Oxford ox2 6dp Oxford University Press is a department of the University of Oxford. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide in Oxford New York Auckland Cape Town Dar es Salaam Hong Kong Karachi Kuala Lumpur Madrid Melbourne Mexico City Nairobi New Delhi Shanghai Taipei Toronto With offices in Argentina Austria Brazil Chile Czech Republic France Greece Guatemala Hungary Italy Japan Poland Portugal Singapore South Korea Switzerland Thailand Turkey Ukraine Vietnam Oxford is a registered trade mark of Oxford University Press in the UK and in certain other countries Published in the United States by Oxford University Press Inc., New York ©Frank Close 2010 The moral rights of the author have been asserted Database right Oxford University Press (maker) First published 2010 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, without the prior permission in writing of Oxford University Press, or as expressly permitted by law, or under terms agreed with the appropriate reprographics rights organization. Enquiries concerning reproduction outside the scope of the above should be sent to the Rights Department, Oxford University Press, at the address above You must not circulate this book in any other binding or cover and you must impose the same condition on any acquirer British Library Cataloguing in Publication Data Data available Library of Congress Cataloging in Publication Data Library of Congress Control Number 2010930302 Typeset by SPI Publisher Services, Pondicherry, India Printed in Great Britain on acid-free paper by Clays Ltd, St Ives ISBN 978-0-19-957459-9 Contents Ray Davis Foreword 1. -
On the Scent of Glue
On the scent of glue by Frank Close Although this work was not new Soon after the quark model was in has been intensifying over the last for the specialists, the underlying vented twenty years ago, people re several years. Where have all the message was clear. 'Because of its alized that it was in trouble. The Pauli flowers gone? inherent singularities, classical gen exclusion principle ruled out many eral relativity predicts its own down well known states, in particular the How colour forces work fall,' stated Hawking, 'just as the configuration of three identical classical picture of the atom was also strange quarks that formed the ome Electrical charges are the sources doomed'. ga-minus. The very hadron whose of electromagnetic forces. As every The meeting merited two closing discovery had confirmed the Eight schoolchild knows, opposite char lectures. For the cosmologists, Mar fold Way seemingly killed its off ges attract while like charges repel. tin Rees of Cambridge confessed to spring, the quark model. Quarks possess electric charge and finding the symposium an 'unusual In those days, many people were so feel electromagnetic forces. That experience'. For the particle physi reluctant to accept the idea of frac is why even electrically uncharged cists, John Ellis described particle tionally charged quarks which had particles like neutrons have electro physics and cosmology as having 'a never been seen. The Pauli paradox magnetic interactions; they contain brilliant past in front of them' — refer suggested that quarks were at best electrically charged constituents. ring to the new common interest in no more than a bookkeeping device, Quarks also have colour and it ap the primaeval Big Bang and its imme not physical particles. -
The Challenge of Neutrinos by Christine Sutton
The challenge of neutrinos by Christine Sutton Neutrino pioneers - left to right, Paul Dirac, Wolfgang Pauli., Rudolf Peierls. (Photo MP Niels Bohr Library) Earlier this year, a team of physicists working at Los Alamos claimed a possible sighting of neutrino oscillations (June, page 13). However even before the claim appeared in the scientific literature, newspaper reports had leaked the possible findings and their implications. Detecting particles which can pass unhindered through the Earth provides the ultimate physics challenge. Neutrinos have always captivated public imagination and make compelling reading. In the wake of the latest neutrino episode, Oxford physi cist and science writer Christine Sutton looks back on the short but volatile history of the neutrino and its attendant publicity. strangers to controversy, for they beta-decay electrons varies continu With the availability of high were in a sense born amidst it, and ously up to a maximum, with peaks energy neutrino beams in the as recent work on neutrino oscilla ("lines") at only a few energies. And 1970s, physicists eagerly tions demonstrates they continue to he was able to explain how the scoured each new batch of data fuel debate. This is of course largely photographic technique could "fake" for signs of exciting new physics. to do with the fact that neutrinos have lines through its great sensitivity to But few initial 'sightings' proved no electric charge and experience small changes in intensity. to be of substance. One of the only the weak nuclear force, making The First World War interrupted major problems faced by such them supremely difficult to detect. -
Taking the Subatomic Grand Tour the Secrets of the World of Elementary Particles Revealed
book reviews Taking the subatomic Grand Tour The secrets of the world of elementary particles revealed. The Particle Odyssey: A Journey to the Heart of Matter by Frank Close, Michael Marten & FERMILAB Christine Sutton Oxford University Press: 2002. 246 pp. £29.95, $45. Ken Peach The development of the standard model of particles and their interactions is one of the major scientific achievements of the twen- tieth century. The electron was the first ‘elementary particle’ to be discovered, by J. J. Thomson (working largely on his own) in 1897, and the top quark was the last of the standard model’s ‘fundamental fermions’ to be discovered, by two large teams at the Tevatron near Chicago in 1995. In between, special and general relativity, quantum mechanics and a deep understanding of symmetry (explicit and hidden, global and local, absolute and spontaneously broken) have transformed our understanding of the dynamics of the Universe. Within this frame- work, a remarkably complete description of the way in which the Universe works has Problem particle: the top quark, here decaying into muons (blue tracks), wasn’t discovered until 1995. been developed, and all but one of its ingre- dients experimentally verified — only the ingredient (quarks, leptons, gauge bosons tions. Most of the loopholes have since been elusive Higgs particle remains undetected. and other whimsies associated with high- closed: the top quark has now been discov- The Particle Odyssey describes a century energy physics) is described and illustrated, ered, the electroweak sector has survived of discovery and creativity through a series along with photographs and biographical precision scrutiny at the Large Electron– of stunning images and photographs. -
The Great Survivor
Dubna - the great survivor atoms are now around the corner. This year, as CERN celebrates its chine in the world. This machine is The Conference closed with the 40th anniversary (November, page still operational, and features in the award of N. Hamann Prize to A. 26), not far behind in the celebration Guinness Book of records as the Masoni of Cagliari, for his presenta stakes is the Joint Institute for Nu planet's largest electromagnet. tion on a high statistics study of iota clear Research, Dubna, near Mos While eclipsed by the new genera decay with the Obelix spectrometer. cow, established in 1956. While tion of strong focusing machines, the This Prize, funded by the Jozef CERN's goal was to provide a Synchrophasotron enjoyed a new Stefan Institute, Ljubljana, is in physics platform on which to rebuild lease of life as a heavy ion machine memory of Niklaus Hamann, PS Western European science after (up to silicon-28), as well as provid coordinator and LEAR physicist who World War II, JINR had a similar ing polarized deuteron beams. The died last year, aged 40. mission for the USSR and the social machine currently runs for some ist countries, including Eastern 1,500 hours per year, providing Europe. research material for more than 500 The fact that both organizations are scientists from 100 institutions. reaching their 40th anniversary The next energy step had very testifies to their success. While their different scenarios at CERN and at aims were very similar, their political JINR. In in the early 1970s, CERN contexts and scientific strategies decided to build the '300 GeV have led along very different routes. -
Thirty Years of Erice on the Brane1
IMPERIAL-TP-2018-MJD-03 Thirty years of Erice on the brane1 M. J. Duff Institute for Quantum Science and Engineering and Hagler Institute for Advanced Study, Texas A&M University, College Station, TX, 77840, USA & Theoretical Physics, Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom & Mathematical Institute, Andrew Wiles Building, University of Oxford, Oxford OX2 6GG, United Kingdom Abstract After initially meeting with fierce resistance, branes, p-dimensional extended objects which go beyond particles (p = 0) and strings (p = 1), now occupy centre stage in the- oretical physics as microscopic components of M-theory, as the seeds of the AdS/CFT correspondence, as a branch of particle phenomenology, as the higher-dimensional pro- arXiv:1812.11658v2 [hep-th] 16 Jun 2019 genitors of black holes and, via the brane-world, as entire universes in their own right. Notwithstanding this early opposition, Nino Zichichi invited me to to talk about su- permembranes and eleven dimensions at the 1987 School on Subnuclear Physics and has continued to keep Erice on the brane ever since. Here I provide a distillation of my Erice brane lectures and some personal recollections. 1Based on lectures at the International Schools of Subnuclear Physics 1987-2017 and the International Symposium 60 Years of Subnuclear Physics at Bologna, University of Bologna, November 2018. Contents 1 Introduction 5 1.1 Geneva and Erice: a tale of two cities . 5 1.2 Co-authors . 9 1.3 Nomenclature . 9 2 1987 Not the Standard Superstring Review 10 2.1 Vacuum degeneracy and the multiverse . 11 2.2 Supermembranes . -
CERN Courier April 2014 Viewpoint Cividec Instrumentation
CERN Courier April 2014 Viewpoint cividec Instrumentation CIVIDEC Instrumentation is a R&D company born from the cutting-edge technology of CERN. We specialise in turn-key The 1980s: spurring collaboration solutions for beam diagnostics based on CVD diamond technology. Herwig Schopper recalls a transferred to new assignments. Another element of “anti-growth” had decade of growth at CERN. long-term consequences. Council was Diamond Detectors convinced that the scientifi c programme was fi rst class, but had doubts about the effi ciency of management. An evaluation committee The 1980s were characterized was established to assess the human and by two outstanding material resources, with a view to reducing achievements that were to the CERN budget. In the end, the committee infl uence the long-term declined to consider a lower material future of CERN. First came the discovery budget because this would undoubtedly of the W and Z particles, the carriers of the jeopardize the excellent scientifi c record of weak force, produced in proton–antiproton Herwig Schopper in 1982: with LEP a “new CERN. They proposed instead a reduction collisions at the Super Proton Synchrotron ‘sociology’ for international scientifi c of staff from about 3500 to 2500, through (SPS) and detected by the UA1 and UA2 co-operation was born”. (Image credit: an early retirement programme, and during experiments. These were the fi rst, now-typical CERN-PHOTO-8205525.) the construction of the LHC this was even collider experiments, covering the full lowered to 2000. However, to cope with solid angle and requiring large groups the time with Israel and Turkey failed, for the increasing tasks and the rising number of collaborators from many countries.